Thin film field effect transistor liquid crystal display (TFT-LCD for short) is widely used in modern information devices such as television, computer, mobile phone and digital camera due to advantages of being light and thin and having low power consumption and etc. The TFT-LCD is mainly constituted by an array substrate and a color filter substrate. The array substrate comprises a gate electrode, a data line, a pixel electrode and a thin film transistor. When a high voltage is present at the gate electrode, the thin film transistor is turned on, and the pixel electrode is charged through the data line; when a low voltage is present at the gate electrode, the thin film transistor is turned off, and the stored voltage of the pixel electrode will last till the thin film transistor is turned on the next time.
The array substrate in the prior art is a single gate structure, as there is overlap between the gate electrode and the drain electrode in the thin film transistor, this structure renders a parasitic capacitance Cgd in the thin film transistor. As illustrated in FIG. 1, when the on/off voltage signal from the gate line controls and turns on the thin film transistor, the data voltage signal from the data line starts to charge the pixel electrode, and the pixel charge voltage at the pixel electrode gradually increases to a set value; when the thin film transistor is turned off, that is, the time when the on/off voltage signal is lowered to a low level, the charges stored at the parasitic capacitance Cgd change, then the voltage at the pixel electrode is changed and generates a leaping voltage ΔVp, and then picture flashing is incurred.